Detection and diagnosis of inflammatory disorders

ABSTRACT

Soluble H4 (sH4) levels have been discovered to correlate with the stage or severity of inflammatory disorders including autoimmune disorders. In particular, circulating levels of sH4 can be used as a diagnostic for determining the severity of an inflammatory disorder or the propensity for developing an inflammatory disorder. The severity of an inflammatory disorder can be determined by assaying the levels of sH4 in a subject and comparing the levels of sH4 to reference sH4 concentrations that correlate to specific stages of an inflammatory disorder. The therapeutic efficacy of treatments for inflammatory disorders can also be determined by comparing levels of sH4 before and during treatment. Methods and devices for measuring sH4 are also provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of pending U.S. patent application Ser. No. 11/965,425 which claims benefit of and priority to U.S. Ser. No. 60/877,319 filed on Dec. 27, 2006 and U.S. Ser. No. 60/949,742 filed on Jul. 13, 2007, all of which are incorporated by reference in their entirety.

GOVERNMENT SUPPORT

The Federal Government has certain rights in this invention by virtue of Grant No. RD 1 CA98731 awarded by the National Institutes of Health to Lieping Chen.

FIELD OF THE INVENTION

The invention is generally related to compositions and methods for detecting and assisting in the diagnosis of inflammatory disorders, including but not limited to auto-immune disorders.

BACKGROUND OF THE INVENTION

Chronic and persistent inflammation is a major cause for the pathogenesis and progression of systemic autoimmune diseases such as rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE). RA is a highly inflammatory polyarthritis often leading to joint destruction, deformity and loss of function. Additive, symmetric swelling of peripheral joints is the hallmark of the disease. Extra-articular features and systemic symptoms can commonly occur and may antedate the onset of joint symptoms. Chronic pain, disability and excess mortality are unfortunate sequelae. During progression of RA, the synovial lining layer of the inflamed joints increases its thickness as a result of synovial hyperplasia and infiltration into synovial stroma by CD4+ T cells, B cells, CD8+ T cells, macrophages, dendritic cells and neutrophils (Feldmann, M. et al., Cell, 85:307-10 (1996); Moreland, L. W. et al., N Engl J Med, 337:141-7 (1997)). In SLE, the production of autoantibodies results in the deposition of immune complex in many tissues and organs including glomeruli, skin, lungs and synovium, thereby generating rheumatic lesions with characteristic chronic inflammation and tissue damage.

In several arthritis models, depletion of neutrophils resulted in a decrease of arthritis severity. The most common animal model for RA is collagen-induced arthritis (CIA) in which challenge with type II chicken collagen (CII) induces persistent chronic inflammation in all major joints of DBA/II mice (Williams, R. O., et al., Proc Natl Acad Sci USA, 91:2762-6 (1994)). While CD4+ T cells have long been considered to play a central role in the pathogenesis of RA, there is renewed interest in addressing the pivotal role of neutrophils in initiation, progression and maintenance of RA. Massive infiltration of neutrophils in the lesions releases the proinflammatory cytokines including TNF-α, IL-1 and IL-6, which can affect the functions of neutrophils and other inflammatory cells.

An extensively studied murine model for SLE is the 1pr strain, in which mutation of Fas apoptotic gene leads to spontaneous autoimmune disorders similar to human SLE. Studies in this strain recapitulate many aspects of human SLE symptoms. For example, 1pr mice develop anti-chromatin, anti-DNA, and anti-IgG serum autoantibodies as well as a polyclonal increase of total immunoglobulin. Disease severity is highly dependent on genetic background. For example, MRL-1pr/1pr mice produce high levels of IgG autoantibodies to DNA and develop a severe glomerulonephritis due to deposition of immune complexes, while C57BL/6(B6)-1pr/1pr mice produce low level autoantibodies with much mild immunopathology.

Co-signal molecules, including those with costimulatory and coinhibitory functions, are important for the induction of effective immune response and for the prevention of unwanted auto immunity. It has been shown that signals through the B7-CD28 family are major regulators of this balance and play a pivotal role in the regulation of autoimmunity. Persistence of inflammatory responses in systemic autoimmune diseases implies either an impaired coinhibitory or enhanced costimulatory functions, leading to the loss of the balance. In this regard, it is particularly interesting that autoantibodies against B7-H1, a primary coinhibitory molecule after binding to its receptor PD-1, is found in a significant proportion of RA patients and the presence of the autoantibodies is implicated in the progression of RA symptoms.

Soluble forms of B7-CD28 family molecules are also implicated in the progression of rheumatoid diseases. A recent study shows that soluble PD-1 could be detected in RA patients and the levels of soluble PD-1 are correlated with WNF-alpha concentration in synovial fluid. B7-H4 is a more recent addition to the B7 family member. B7-H4 has potent inhibitory effects on T cells through binding to a putative receptor. Cell surface B7-H4 is normally not detectable in normal tissues, although its surface expression could be upregulated on macrophages and tumor cells by inflammatory cytokines, including IL-10 and IL-6. It has been reported that B7-H4 could suppress T cell response in the presence of antigen stimulation. Soluble B7-H4 (sH4) has also been detected in ovarian cancer patients as a potential biomarker, but the mechanism of production and the function of sH4 is unknown. B7-H4 deficient mice were found to mount slightly enhanced T helper 1 type T cell responses against Leishmania major infection. Using independently generated B7-H4 knockout mice, it was demonstrated that the lack of B7-H4 led to resistance to Listeria monocytogenes infection occurs by direct regulation of growth of neutrophil progenitors. Methods and devices for detecting and quantifying sH4 are needed to explore the role sH4 plays in inflammatory disorders including autoimmune disorders.

It is an object of the invention to provide methods and devices for detecting or quantifying levels of sH4 in a subject.

It is another object of the invention to provide methods and devices for determining the stage or progression of an inflammatory disorder in a subject.

It is still another object of the invention to provide methods and devices to diagnose or to assist in the diagnosis of an inflammatory disorder.

SUMMARY OF THE INVENTION

Soluble H4 (sH4) levels have been discovered to correlate with the stage or severity of inflammatory diseases and disorders including autoimmune disorders. In particular, circulating levels of sH4 can be used as a diagnostic for determining the severity of an inflammatory disease or disorder or the propensity for developing an inflammatory disease or disorder. The severity of an inflammatory disease or disorder can be determined by assaying the levels of sH4 in a subject and comparing the levels of sH4 to reference sH4 concentrations that correlate to specific stages of an inflammatory disease or disorder.

Representative inflammatory diseases and disorders include, but are not limited to rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura (ATP), Blehcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis, dermatomyositis-juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia-fibromyositis, grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type 1), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.

One embodiment provides a method for assisting in the diagnosis of an inflammatory disease or disorder or propensity of developing an inflammatory disease or disorder in a subject by obtaining a biological sample from the subject and determining levels of sH4 in the biological sample, wherein elevated levels of sH4 in the biological sample relative to a control is indicative of an inflammatory disease or disorder or an increased propensity for developing an inflammatory disease or disorder.

Still another embodiment provides a method for determining the therapeutic efficacy of a treatment for an inflammatory disease or disorder by obtaining biological samples from a subject at various time intervals during treatment and comparing the levels of sH4 in the samples to levels of sH4 in a biological sample obtained from the subject prior to treatment. Additionally, or alternatively, the levels of sH4 in the biological samples obtained from the subject during treatment can be compared to levels of sH4 indicative of different stages of an inflammatory disease or disorder or autoimmune disease.

Yet another embodiment provides a lateral flow device for determining sH4 concentration in a subject. The device includes an application zone for receiving a fluid sample, a labeling zone containing labeled binding partner for the sH4, and a detection zone having an immobilized capture reagent for the sH4. The device also includes a reference zone having a signal of fixed intensity indicative of the reference concentration of sH4, wherein when the signal in the detection zone is less intense than the signal in the reference zone, the subject has a sH4 level less than the reference concentration, and when the signal in the detection zone is more intense than the signal in the reference zone, the subject has a sH4 level more than the reference concentration.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a is a graph showing sH4 in sera of healthy donors (HD) (♦), rheumatoid arthritis (RA) (▴), and systemic lupus erythematosus (SLE) (□) patients. FIG. 1 b is a graph showing the correlation between concentration of the sH4 and the severity groups 0 (▴), 1 (X), 2 (♦), and 3 (▪) of RA.

FIG. 2 shows an exemplary lateral flow device.

FIG. 3 shows the lateral flow device in a housing.

DETAILED DESCRIPTION OF THE INVENTION I. Definitions

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.

The term “effective amount” or “therapeutically effective amount” means a dosage sufficient to provide treatment of the inflammatory response or autoimmune disease state being treated or to otherwise provide a desired pharmacologic and/or physiologic effect. The precise dosage will vary according to a variety of factors such as subject-dependent variables (e.g., age, immune system health, etc.), the disease, and the treatment being effected.

A “fragment” of a B7-H4 polypeptide is a fragment of the polypeptide that is shorter than the full-length polypeptide. Generally, fragments will be five or more amino acids in length. An antigenic fragment has the ability to be recognized and bound by an antibody.

The terms “individual,” “host” “subject,” and “patient” are used interchangeably herein, and refer to a mammal, including, but not limited to, humans, rodents, such as mice and rats, and other laboratory animals.

The terms “polypeptide” and “protein” are used interchangeably and mean any peptide-linked chain of amino acids, regardless of length or post-translational modification.

The term “sH4” refers to soluble B7-H4. sH4 includes the extracellular domain of 37-H4 and biologically active fragments thereof. Human and mouse B7 proteins contain short intracytoplasmic domains, a single transmembrane, domain and an extracellular domain. The extracellular domain typically contains two Ig domains; a membrane proximal IgC domain and a membrane distal IgV domain. B7-H4 nucleotide and protein sequence are found in GENBANK under accession number AY280972. Additionally, B7-H4 is described in U.S. Pat. No. 6,891,030 and where permissible, is incorporated by reference in its entirety. As used herein, the terms “soluble B7-H4” and “sH4” encompass any polypeptide fragment of B7-H4 that is shed, secreted or otherwise extracted from the producing cells in vivo. Soluble B7-H4 is typically approximately 50-kDa by Western blot analysis, a size equal to the entire extracellular domain of monomeric B7-H4 molecule in denatured condition.

As used herein, the term “treating” includes alleviating, preventing and/or eliminating one or more symptoms associated with inflammatory responses or an autoimmune disease. Representative inflammatory diseases or disorders include, but are not limited to, autoimmune diseases or disorders including rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (ALPS), autoimmune thrombocytopenic purpura (ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, clronic fatigue syndrome immune deficiency syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis, dermatomyositis-juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia-fibromyositis, grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type I), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.

II. Diagnostics

A. Detection of sH4 for Diagnosis of Disease and Disease States

Soluble B7-H4 is found in sera of approximately two-thirds of patients having rheumatoid arthritis (RA) and one-third of the systemic lupus erythematosus (SLE) patients sampled. The concentration of sH4 in an individual correlates closely with the severity, stage and progression of inflammation, particularly in autoimmune diseases (FIGS. 1 a and 1 b). In an experimental mouse model of RA and SLE, the effect of sH4 was recapitulated, and it was demonstrated that sH4 acts as a decoy to block suppressive functions of endogenous B7-H4, leading to exacerbation of systemic autoimmune diseases. The results demonstrate a role of sH4 in the pathogenesis of systemic autoimmune diseases.

An inflammatory response or condition in an individual can be diagnosed or detected by quantifying the amount of sH4 in a biological sample of the individual, wherein an elevated amount of sH4 in the individual's biological sample compared to a control (single or more preferably pooled or averaged values of normal individuals in the same assay) is indicative of an inflammatory response, preferably an auto-immune disease. A biological sample includes tissue or biological fluid such as a fluid from the individual, for example, blood, plasma, saliva, lymph, cerebrospinal fluid, synovial fluid, urine, or sputum. A control refers to a biological sample from an individual not experiencing an inflammatory response such as an autoimmune disease.

The amount of sH4 in a sample can be determined using conventional techniques such as enzyme-linked immunosorbent assays, mass spectrometry, spectrophotometry, or a combination thereof.

B7-H4 nucleotide and protein sequences are found in GENBANK under accession number AY280972. Additionally, 137-H4 is described in U.S. Pat. No. 6,891,030 and where permissible, is incorporated by reference in its entirety. One of ordinary skill in the art can determine the extracellular domain of B7-H4 based on these sequences.

In one embodiment, the sH4 that can be detected in a sample includes the membrane distal IgV domain and the membrane proximal IgC domain of B7-H4. In another embodiment the sH4 that is detected includes an amino acid sequence that is 80%, 85%, 90%, 95%, or 99% to the following amino acid sequences:

In another embodiment, the sH4 that is detected includes the IgV domain of B7-H4 includes an amino acid sequence that has at least 80%, 85%, 90%, 95%, or 99% sequence identity to:

In yet another embodiment, the sH4 that is detected includes a fragment of B7-H4 having an amino acid sequence that has at least 80%, 85%, 90%, 95%, or 99% sequence identity to:

In still another embodiment, the sH4 that is detected is a fragment of B7-H4 having the following amino acid sequence having an amino acid sequence that has at least 80%, 85%, 90%, 95%, or 99% sequence identity to:

The propensity of the subject developing or having an inflammatory disorder can be determined based on the levels of sH4 in the subject, preferably serum levels of sH4 in the subject. If the levels of sH4 in the subject are higher than the average sH4 levels in subjects without inflammatory disorders, the subject is more likely to develop an inflammatory disorder or to have an inflammatory disorder.

The severity of an inflammatory response or an autoimmune disease can be detected or assessed by quantifying the level of sH4 in an individual's biological sample and correlating the amount of sH4 in the individual's biological sample with amount(s) of sH4 indicative of different stages of an inflammatory response or autoimmune disease. The amounts of sH4 that correlate with different stages of inflammatory disease or different levels of severity can be predetermined by quantifying sH4 in patients at different stages of inflammatory disease, or with different severity of disease. For example, with RA the following classification for severity is typically employed: Class I: No restriction of ability to perform normal activities; Class II: Moderate restriction, but with an ability to perform most activities of daily living; Class III: Marked restriction, with an inability to perform most activities of daily living and occupation; and Class IV. Incapacitation with confinement to bed or wheelchair. Levels of sH4 can be determined in patients from each classification to produce a reference level of sH4 that can be correlated with the specific severity level.

1. Methods of Detecting sH4 in a Biological Sample Using Antibodies

Certain embodiments provide methods for detecting the presence and/or measuring a level of sH4 in a biological sample, using an sH4-specific antibody or an anti-B7-H4 antibody. Preferably the antibody recognizes an epitope on any one of the polypeptides encoded by SEQ ID NOs: 1-6. The methods generally include:

a) contacting the sample with an antibody specific for sH4; and

b) detecting binding between the antibody and molecules of the sample.

Detection of specific binding of the sH4-specific antibody, when compared to a suitable control, is an indication that sH4 is present in the sample. Suitable controls include a sample known not to contain sH4, and a sample contacted with an antibody not specific for sH4, e.g., an anti-idiotype antibody. A variety of methods to detect specific antibody-antigen interactions are known in the art and can be used in the method, including, but not limited to, standard immunohistological methods, immunoprecipitation, an enzyme immunoassay, and a radioimmunoassay. In general, the sH4-specific antibody will be detectably labeled, either directly or indirectly. Direct labels include radioisotopes; enzymes whose products are detectable (e.g., luciferase, β-galactosidase, and the like); fluorescent labels (e.g., fluorescein isothiocyanate, rhodamine, phycoerythrin, and the like); fluorescence emitting metals, e.g., ¹⁵²Eu, or others of the lanthanide series, attached to the antibody through metal chelating groups such as EDTA; chemiluminescent compounds, e.g., luminol, isoluminol, acridinium salts, and the like; bioluminescent compounds, e.g., luciferin, aequorin (green fluorescent protein), and the like. The antibody may be attached (coupled) to an insoluble support, such as a polystyrene plate or a bead. Indirect labels include second antibodies specific for sH4-specific antibodies, wherein the second antibody is labeled as described above; and optionally contain members of specific binding pairs, e.g., biotin-avidin, and the like. The biological sample may be brought into contact with and immobilized on a solid support or carrier, such as nitrocellulose, that is capable of immobilizing cells, cell particles, or soluble proteins. The support may then be washed with suitable buffers, followed by contacting with a detectably-labeled sH4-specific antibody.

Still other embodiments provide methods for detecting the presence and/or measuring a level of sH4 in a biological sample. The methods generally include:

a) contacting the sample with an sH4 ligand, for example a B7-H4 receptor or fragment thereof that binds sH4; and

b) detecting binding between the B7-H4 receptor and molecules of the sample.

Detection of specific binding of the B7-H4 receptor is an indication that sH4 polypeptides are present in the sample.

Methods for detecting binding between a B7-H4 receptor and sH4 are known in the art and include immunoprecipitation of B7-H4 receptor-ligand complexes using an antibody specific to the B7-H4 receptor, as long as the antibody does not disrupt 137-H4 receptor sH4 binding. Alternatively, the B7-H4 receptor used may be a fusion protein which provides for specific immunoprecipitation of the fusion partner, an enzymatic detection, a fluorescent signal (e.g., a green fluorescent protein). The B7-H4 receptor can be labeled with any detectable label, as described above, The B7-H4 receptor can be attached, directly or through a linker, to an insoluble support (e.g., polystyrene beads, magnetic beads, and the like), thereby providing a means for separating sH4/receptor complexes from the biological sample, and subsequently detecting the presence of and/or measuring the amount (level) of sH4. The latter method can also be used to identify new proteins that bind to the 137-H4 receptor.

2. Methods of Determining Therapeutic Efficacy of Drug Treatment in an Individual

The therapeutic efficacy of a treatment for an inflammatory disease or disorder or an autoimmune disease can be assessed by quantifying the level of sH4 in an individual's biological sample over the course of treatment. Levels of sH4 present in a biological sample from the individual can be determined prior to treatment and subsequently at various time intervals during treatment. The levels of sH4 present in the biological sample of the individual undergoing treatment can be compared to the levels of sH4 present in biological samples from the same individual prior to treatment to determine the efficacy of the treatment in reducing or inhibiting the inflammatory disease or disorder. The levels of sH4 in biological samples of the individual undergoing treatment can additionally or alternatively be compared to amounts of sH4 indicative of different stages of an inflammatory response or autoimmune disease.

3. Methods of Determining Neutrophil Levels in a Biological Sample.

Alternatively, the amount of sH4 can be correlated to levels of neutrophils. In certain individuals with inflammatory responses or autoimmune disease, sH4 concentration is elevated as are levels of neutrophils. Thus, sH4 levels in an individual can be correlated to neutrophil levels. Levels of sH4 that correspond to specific levels of neutrophils can be predetermined by assaying the levels of sH4 in subjects and assaying the levels of neutrophils in the subjects. Once the reference levels are determined, a biological sample from a subject can be assayed for sH4 levels. The resulting sH4 levels are then compared to the predetermined sH4 levels correlated to specific levels of neutrophils. The resulting sH4 levels are matched to the predetermined levels to determine the neutrophils levels in the subject. The number of neutrophils in a healthy individual ranges from about 15,000 to 20,000 cells/μl.

4. Inflammatory Disorders to be Detected

Representative inflammatory responses or autoimmune diseases that can be detected or assessed for severity include, but are not limited to, rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura (ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis, dermatomyositis-juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia-fibromyositis, grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type I), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.

B. Kits and Detection Devices

A lateral flow device for indicating the presence or concentration of sH4 in a sample is provided. The device can be a component of a kit. The components of the kit are typically packaged in a container suitable for shipping. The kit can include reagents, buffers, and instructions for using the lateral flow device.

An exemplary lateral flow device includes a solid support having an application zone for receiving a fluid sample from a subject, a labeling zone containing label which binds to sH4 in the sample, and a detection zone where sH4-bound label is retained. Label retained in the detection zone gives a signal, and the signal differs depending on whether sH4 levels are lower than or equal to/greater than a given reference concentration. FIGS. 1 a and 1 b show exemplary ranges of the concentrations of sH4 detected in samples from patients. The mean concentration of sH4 in patients having RA or SLE is approximately 100 ng/ml.

The application zone in the device is suitable for receiving a fluid sample. It is typically formed from absorbent material such as blotting paper. The labeling zone contains label which binds to any sH4 in the fluid sample. For reasons of specificity, the label is typically antibody. For ease of detection, the label is preferably visible to the naked eye e.g. it is tagged with a fluorescent tag or, preferably, a colored tag such as conjugated colloidal gold, which is visible as a pink color.

The detection zone retains sH4 to which label has bound. This will typically be achieved using an immobilized capture reagent, such as an antibody. Where the capture reagent and the label are both antibodies, they will recognize different epitopes on sH4. This allows the formation of a “sandwich” comprising antibody-sH4-antibody.

The detection zone is downstream of the application zone, with the labeling zone typically located between the two. A fluid sample will thus migrate from the application zone into the labeling zone, where any sH4 in the sample binds to the label. sH4-label complexes continue to migrate into the detection zone together with excess label. When the sH4-label complex encounters the capture reagent, the complex is retained while the sample and excess label continue to migrate. As sH4 levels in the sample increase, the amount of label (in the form of sH4-label complex) retained in the detection zone increases proportionally.

One type of device includes a reference zone which includes a signal of fixed intensity against which the amount of label retained in the detection zone can be compared—when the signal in the detection zone equals the signal in the reference zone, the sample is a threshold sample; when the signal in the detection zone is less intense than the reference zone, the sample contains less sH4 than a threshold sample; when the signal in the detection zone is more intense than the reference zone, the sample contains more sH4 than a threshold sample. A suitable reference zone can be prepared and calibrated without difficulty. For this type of device, label will generally be present in excess to sH4 in the sample, and the reference zone may be upstream or, preferably, downstream of the detection zone. It is apparent that the signal in the reference zone will be of the same type as the signal in the detection zone i.e. they will typically both be visible to the naked eye e.g. they will use the same tag. A preferred reference zone in a device of this type includes immobilized protein (e.g., bovine serum albumin) which is tagged with colloidal gold.

In another device, the reference zone is downstream of the detection zone and includes a reagent which captures label (e.g. an immobilized anti-label antibody). Label which flows through the device is not present in excess, but is at a concentration such that 50% of it is bound by a sample having sH4 at the threshold concentration. In a threshold sample, therefore, 50% of the label will be retained in the detection zone and 50% in the reference zone. If the sH4 level in the sample is greater than in a threshold sample, less than 50% of the label will reach the reference zone and the detection zone will give a more intense signal than the reference zone; conversely, if the sH4 level in the sample is less than in a threshold sample, less than 50% of the label will be retained in the detection zone and the reference zone will give a more intense signal than the detection zone.

In another embodiment, the reference zone is downstream of the detection zone and includes a limiting amount of a reagent which captures label (e.g. an immobilized anti-label antibody). The reagent is present at a level such that it retains the same amount of label which would bind to detection zone for a threshold sample, with excess label continuing to migrate beyond the reference zone.

In these three types of device, therefore, a comparison between the detection zone and the reference zone is used to compare the sample with the threshold concentration. The detection:reference binding ratio can preferably be determined by eye. Close juxtaposition of the detection and reference zones is preferred in order to facilitate visual comparison of the signal intensities in the two zones.

In a fourth type of device, no reference zone is needed, but the detection zone is configured such that it gives an essentially on/off response i.e. no signal is given below the threshold concentration but, at or above the threshold, signal is given.

In a fifth type of device, no reference zone is needed, but an external reference is used which corresponds to the threshold concentration. This can take various forms e.g. a printed card against which the signal in the detection zone can be compared, or a machine reader which compares an absolute value measured in the detection zone (e.g. a calorimetric signal) against a reference value stored in the machine.

In some embodiments, the device includes a control zone downstream of the detection zone. This will generally be used to capture excess label which passes through the detection and/or reference zones (e.g. using immobilized anti-label antibody). When label is retained at the control zone, this confirms that mobilization of the label and migration through the device have both occurred. It will be appreciated that this function may be achieved by the reference zone.

The detection, reference and control zones are preferably formed on nitrocellulose.

Migration from the application zone to the detection zone will generally be assisted by a wick downstream of the detection zone to aid capillary movement. This wick is typically formed from absorbent material such as blotting or chromatography paper.

The device can be produced simply and cheaply, conveniently in the form of a dipstick.

FIG. 2 shows an exemplary lateral flow device. The test strip (1) of can be constructed on a plastic backing sheet. A strip of nitrocellulose membrane (20) (Millipore Corporation, Product Code HF135) is optionally placed onto the backing sheet. An upper wick (30) formed from blotting paper grade material (Ahlstrom Filtration, Product Code 222) is placed on top of the nitrocellulose at one end, with a partial overlap. At the other end, a polyester pad (40) is placed over the nitrocellulose (20), and a piece of absorbent paper (50) is placed on top of the pad (40). Paper (50) and pad (40) can overlap.

One end (45) is sprayed with colloidal gold (40 nm) conjugated to murine monoclonal antibody to B7-H4 or sH4. 3 microliters of OD10 gold conjugate is applied per test strip. To measure the concentration of gold particles in a given reagent sample, the conjugate under test is diluted to give an OD₅₂₀ nm of about 1.0, and this is multiplied by the dilution factor to give an equivalent OD for the original reagent sample.

The end (45) containing the antibody is not covered by paper (50) and overlaps nitrocellulose (20).

The nitrocellulose strip (20) contains three stripes of reagents. The first stripe (21) is downstream of area (45) and includes monoclonal anti-B7-H4 or anti sH4, applied by striping (1 μl/cm of 0.75 mg/ml antibody). The second and optional stripe (22) is downstream of area (45) and includes colloidal gold (40 nm) conjugated to BSA, applied by striping (1 μl/cm, target OD 3.5). The third stripe (23) is 17 mm downstream of area (45) and includes goat anti-mouse antibody (Jackson Immunoresearch Labs Inc., Product Code 115-005-062), applied by striping (1 μl/cm of 1.5 mg/ml antibody). The device thus has excess free label.

The assembled strip (1) can be mounted in a plastic housing (60; Advanced Microdevices 8 mm cassette) having a window (65) through which a fluid sample can be applied to absorbent paper (50) and a window (68) through which stripes (21), (22) and (23) are visible.

During use of the device, a fluid sample is applied to absorbent paper (50). Lateral flow along the device (1) commences and the sample passes into pad (40) and through area (45), where any sH4 in the sample binds to labeled anti-B7-H4 or anti-sH4. Flow continues into nitrocellulose strip (20). At stripe (21), sH4-antibody complex is retained by immobilized antibodies to sH4 that recognize a different epitope on sH4 than the labeled antibody, but free labeled antibody continues to stripe (23), where it is bound and retained by immobilized goat-anti-mouse antibodies.

EXAMPLE Soluble B7-H4 in the Sera of Rheumatoid Arthritis Patients Correlates with disease severity

Patients and Healthy Donors:

Sera samples were obtained from 68 patients with diagnosed RA, 35 patients with diagnosed SLE and 24 normal healthy donors under approval of the Internal Review Board of Mayo Clinic. RA patients were classified to 4 groups as follows. 0: no active disease, 1: 1-4 active joints, 2: 5-9 active joints, 3: more than 10 active joints with or without extraarticular disease.

Detection of Soluble B7-H4 Collagen-Specific Autoantibodies and Anti-dsDNA Autoantibody:

For detection of human sH4, specific mAb hH4.3 (2 μg/ml) and hH4.1 (2 μg/ml) against human B7-H4 was used as capture and detection, respectively, in ELISA. To remove Rheumatoid Factor, the sera were treated with human IgG agarose (Sigma-Aldrich, St. Louis, Mo.) before detection in ELISA. For measurement of collagen-specific autoantibodies, chicken collagen (1 μg/ml) was coated on the plate overnight at 4° C., and biotin conjugated anti-mouse IgG, IgG1, IgG2a and IgG2b Ab (BD, San Jose, Calif.) as detection antibodies. To measure anti-dsDNA autoantibody levels, dsDNA from salmon testes at 10 μg/ml in PBS was coated on the plate overnight at 4° C., and HRP conjugated anti-mouse IgG, (BD, San Jose, Calif.).

Western Blot:

The sera was mixed with 2× sample buffer (4% SDS, 0.2% bromophenol blue, 20% glycerol in 100 mM Tris buffered saline) and boiled for 5 min. The samples were electrophoresed under reducing conditions on a 10% Ready gel (Bio-Rad, Richmond, Calif.) and the proteins electroblotted onto Protran BA85 (Whatman, Florham Park, N.J.). The Immobilon-P sheet was blocked in 5% nonfat dry milk in PBS for 1 h and incubated with the antibody at 4° C. overnight. After repeated washing (five times 5 min), bound antibody was detected with horseradish peroxidase (HRP)-labeled.

Results

To detect sH4, sera from individual patients with diagnosis of rheumatoid arthritis based on American Rheumatism Association criteria were analyzed by enzyme-linked immunosorbent assays (ELISA) using two specific monoclonal antibodies (mAb) binding to different epitopes on human B37-H4. In this assay, 65% (44 out of 68) samples from patients with RA and 43% (15/35) from patients with SLE were above background and therefore positive. Evaluation of sH4 in healthy donors (HD) showed only 13% (3/24) were positive (FIG. 1 a). sH4 is significantly higher in RA and SLE patients than healthy donors (P<0.05). In addition, the mean concentration of sH4 in RA (96.1 ng/ml) and SLE (36.9 ng/ml) was significantly higher than those of the healthy donors (3.8 ng/ml). The results indicate that sH4 is elevated in a significant portion of RA and SLE patients.

Western blot analysis was used to validate the presence of sH4 in sera from 3 patients with rheumatoid arthritis. Using specific mAb against B7-H4, the sera from 3 RA patients, who have detectable sH4 in ELISA, showed a single 50-kDa band. This matched the size of predicted extracellular domain of human B7-H4. In contrast, no band was observed in sera from three healthy donors. The data support the presence of sH4 in the sera of RA patients.

The association of elevated concentration of sH4 with the severity of RA was investigated. Based on severity of diseases, 68 RA patients were classified into 4 groups (0-3) with most severe diseases in group 3 as described in Methods. The mean concentration of sH4 in group 3 (260.7 ng/ml) was significantly higher than those of group 0 (22.0 ng/ml) or Group 1 (18.8 ng/ml). However, there was no significant difference among group 0-2 by Scheffe test (FIG. 1 b). The data thus indicate that RA patients in group 3 have highest level sH4 and suggest that sH4 might play a role in the progression of severe RA.

Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of skill in the art to which the disclosed invention belongs. Publications cited herein and the materials for which they are cited are specifically incorporated by reference.

Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims. 

1. A method for determining the severity of an inflammatory disorder comprising determining levels of sH4 in a subject and comparing the levels of sH4 to reference sH4 concentrations that correlate to specific stages of an inflammatory disorder.
 2. The method of claim 1 wherein the inflammatory disorder is selected from the group consisting of rheumatoid arthritis, systemic lupus erythematosus, alopecia areata, anklosing spondylitis, antiphospholipid syndrome, autoimmune Addison's disease, autoimmune hemolytic anemia, autoimmune hepatitis, autoimmune inner ear disease, autoimmune lymphoproliferative syndrome (alps), autoimmune thrombocytopenic purpura (ATP), Behcet's disease, bullous pemphigoid, cardiomyopathy, celiac sprue-dermatitis, chronic fatigue syndrome immune deficiency, syndrome (CFIDS), chronic inflammatory demyelinating polyneuropathy, cicatricial pemphigoid, cold agglutinin disease, Crest syndrome, Crohn's disease, Dego's disease, dermatomyositis, dermatomyositis—juvenile, discoid lupus, essential mixed cryoglobulinemia, fibromyalgia—fibromyositis, grave's disease, guillain-barre, hashimoto's thyroiditis, idiopathic pulmonary fibrosis, idiopathic thrombocytopenia purpura (ITP), Iga nephropathy, insulin dependent diabetes (Type I), juvenile arthritis, Meniere's disease, mixed connective tissue disease, multiple sclerosis, myasthenia gravis, pemphigus vulgaris, pernicious anemia, polyarteritis nodosa, polychondritis, polyglancular syndromes, polymyalgia rheumatica, polymyositis and dermatomyositis, primary agammaglobulinemia, primary biliary cirrhosis, psoriasis, Raynaud's phenomenon, Reiter's syndrome, rheumatic fever, sarcoidosis, scleroderma, Sjogren's syndrome, stiff-man syndrome, Takayasu arteritis, temporal arteritis/giant cell arteritis, ulcerative colitis, uveitis, vasculitis, vitiligo, and Wegener's granulomatosis.
 3. The method of claim 1 wherein the sH4 levels are determined from a fluid sample obtained from the subject.
 4. The method of claim 3 wherein the fluid sample is selected from the group consisting of blood, plasma, saliva, lymph, cerebrospinal fluid, synovial fluid, urine, and sputum.
 5. The method of claim 1 wherein levels of sH4 are determined using mass spectroscopy, immunohistological methods, immunoprecipitation, an enzyme immunoassay, and a radioimmunoassay.
 6. A method for assisting in the diagnosis of an inflammatory disorder or propensity of developing an inflammatory disorder in a subject comprising obtaining a biological sample from the subject; determining levels of sH4 in the biological sample, wherein elevated levels of sH4 in the biological sample relative to a control is indicative of an inflammatory disorder or an increased propensity for developing an inflammatory disorder.
 7. The method of claim 6 wherein the biological sample is selected from the group consisting of blood, plasma, saliva, lymph, cerebrospinal fluid, synovial fluid, urine, and sputum.
 8. The method of claim 6 wherein levels of sH4 are determined using mass spectroscopy, immunohistological methods, immunoprecipitation, an enzyme immunoassay, and a radioimmunoassay.
 9. A method for determining the efficacy of a treatment for an inflammatory disorder in a subject comprising obtaining one or more biological samples from the subject during the course of the treatment, and comparing the levels of sH4 in the samples to the levels of sH4 in a biological sample obtained from the subject prior to treatment, or comparing the levels of sH4 in the samples to levels of sH4 indicative of different stages of an inflammatory disease or disorder or autoimmune disease.
 10. The method of claim 6 wherein the biological sample is selected from the group consisting of blood, plasma, saliva, lymph, cerebrospinal fluid, synovial fluid, urine, and sputum.
 11. The method of claim 6 wherein levels of sH4 are determined using mass spectroscopy, immunohistological methods, immunoprecipitation, an enzyme immunoassay, and a radioimmunoassay.
 12. A lateral flow device for determining sH4 concentration in a subject comprising: (a) an application zone for receiving a fluid sample; (b) a labeling zone containing labeled binding partner for the sH4; (c) a detection zone having an immobilized capture reagent for the sH4; and (d) a reference zone having a signal of fixed intensity indicative of the reference concentration of sH4, wherein when the signal in the detection zone is less intense than the signal in the reference zone, the subject has a sH4 level less than the reference concentration; and when the signal in the detection zone is more intense than the signal in the reference zone, the subject has a sH4 level more than the reference concentration.
 13. The lateral flow device of claim 12 wherein the labeled binding partner of the sH4 is an antibody or antigen binding fragment thereof.
 14. The lateral flow device of claim 12 wherein the fluid sample is selected from the group consisting of blood, plasma, saliva, lymph, cerebrospinal fluid, synovial fluid, urine, and sputum.
 15. A method for measuring sH4, comprising (a) obtaining a blood sample from a subject; (b) applying the blood sample to the application zone of the lateral flow device according to claim 12; (c) detecting a signal in the detection zone of the lateral flow device; and (d) comparing the signal detected in step (c) with the signal in the reference zone, wherein when the signal in the detection zone is less intense than the signal in the reference zone, the subject has normal sH4 levels; and when the signal in the detection zone is equal to or more intense than the signal in the reference zone, the subject has elevated sH4 levels.
 16. A method for determining neutrophils levels of a subject comprising obtaining a biological sample from the subject; determining levels of sH4 in the biological sample; comparing the levels of sH4 in the biological sample to predetermined levels of sH4 correlating to levels of neutrophils; and selecting the level of neutrophils that matches the levels of sH4 in the biological sample.
 17. The method of claim 16 wherein elevated levels of sH4 relative to a control are indicative of elevated levels of neutrophils relative to a control.
 18. A kit comprising the lateral flow device of claim 12, reagents for using the kit, and instructions for using the kit. 